1. Field of the Invention
The present invention relates to a ceramic substrate composition which can be fired at a temperature of up to 1000xc2x0 C. and a ceramic circuit component produced by use of the same such as a multilayer integrated circuit, a thick-film hybrid circuit, or the like.
2. Description of the Related Art
The conventional, main stream ceramic substrates for use in ceramic circuit components have been alumina substrates. However, the alumina substrates are required to be fired at a high temperature, namely, at about 1600xc2x0 C. To obtain a multilayer substrate, there is a need to use a metal having a high melting point such as W, Mo, or the like as an internal conductor. However, since these metals with a high melting point have a relatively high electric resistance, the alumina substrates are unsuitable for use as the multilayer substrates in electronic components which are required to be used at high frequencies and speeds. Accordingly, greater attention, has been given to development of ceramic substrates having a low dielectric constant and capable of fired at a low temperature, that is, which have a firing temperature of up to 1000xc2x0 C. so that the ceramic substrates can be fired together with metals such as Au, Ag, Agxe2x80x94Pd, Agxe2x80x94Pt, Cu, and the like.
With the conventional ceramic substrates capable of being fired at a low temperature, it has been much difficult to satisfy the requirements for a low dielectric constant, low loss, and high strength at the same time. Further, there is the problem that when an Ag type electrode is fired together with the substrates capable of being fired at a low temperature, Ag is diffused into the substrates during the firing.
Accordingly, it is an object of the present invention to provide a ceramic substrate composition which satisfies requirements for a low dielectric constant, low loss, and high strength, and which can be fired together with an Ag type electrode while the Ag is prevented from being diffused into the ceramic substrate, and to provide a ceramic circuit component produced by use of the ceramic substrate composition.
According to the present invention, there is provided a ceramic substrate composition which contains about 26 to 48% by weight of a CaOxe2x80x94Al2O3xe2x80x94B2O3xe2x80x94SiO2 type glass, about 35 to 68% by weight of at least one kind of ceramic selected from the group consisting of alumina, mullite, cordierite and forsterite, and about 3 to 24% by weight of quartz, said glass being capable of being partially crystallized to wollastonite by firing the composition at a temperature of about 800 to 1000xc2x0 C.
Preferably, the ceramic substrate composition contains up to about 5% by weight of at least one kind of alkali metal oxide selected from the group consisting of Li2O, K2O and Na2O.
Also preferably, the ceramic substrate composition contains up to about 5% by weight of at least one kind of metal oxide selected from the group consisting of TiO2, ZrO2, CrO2 and CuO.
Further, according to the present invention, there is provided a ceramic circuit component which contains a conductor circuit formed on a ceramic substrate produced by molding and firing the above ceramic substrate composition.
The conductor circuit may contain at least one member selected from the group consisting of Ag, Au and Cu as a major component.